


every door you enter, I will let you in

by Tiara_of_Sapphires



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Barebacking, Double Penetration, Explicit Sexual Content, F/M, Slight Dom/Sub, Xenophilia, no beta we die like Glenn
Language: English
Status: Completed
Published: 2020-07-19
Updated: 2020-07-19
Packaged: 2021-03-04 18:26:58
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,822
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25390852
Author URL: https://archiveofourown.org/users/Tiara_of_Sapphires/pseuds/Tiara_of_Sapphires
Summary: Nabetean biology is a strange thing and Byleth is okay with that.
Relationships: My Unit | Byleth/Seteth
Comments: 8
Kudos: 114





	every door you enter, I will let you in

**Author's Note:**

> Idk the title of this is based off of “What’s My Name” by Rihanna because the line is the biggest double-entendre ever and it’s hilarious.
> 
> Another plot bunny that I decided to work on while on my hiatus.  
> Enjoy!

Byleth shivered as a hand stroked over her back. She buried her face into her crossed arms and pressed her forehead against them as the other hand grabbed at her ass.

She moaned as fingers probed and pressed in for what felt like the hundredth time. “You are going to kill me.”

“Unlikely,” Seteth drawled.

It was easy for him to say, since he wasn’t the one face down, spread out on the bed like a feast, trembling with overstimulation.

Seteth seemed to take particular delight in taking her apart with his hands and mouth, in preparation for what was next.

“I want to make this as pleasurable for you as possible.”

His fingers stroked over her clit, up to where she was dripping with saliva and the oil he used to prep her.

“I’m plenty pleased,” she mumbled. She reached back towards the space between his hips, where his shafts, tapered and pale and inhuman, bobbed in the air.

Byleth had no idea how he was able to hide his extra member in his pants on a daily basis. He had been so shy when the topic of sex came up after the war’s end, as if it would scare her away. She knew his true nature, who and what he was.

While his dragon form had been locked away, part of it had remained. She was glad that he didn't hide it away from her anymore, especially because she found it so appealing now that she knew.

His hips bucked into her touch.

“You really do want it,” Seteth marveled.

“Of course, I do,” she said, matter-of-fact. “I want you any way I can have you.”

At that point, he had already made her come so many times with his mouth and hands that she would’ve been fine with sliding down to her knees or flipping around in bed to let him use her mouth. It was his pleasure, the newness of this aspect of their relationship that interested her the most.

He had been so restrained in their first trysts, keeping his smallclothes on at all times while he focused on pleasing her. He had always insisted that it wasn’t about him, only about her. At the time, she had been sure it was just his gentlemanly demeanor. While she did have opportunities to grind on him until he came in his pants or tweaked his nipples or sucked bruises onto his throat, it wasn’t the same as having him fully exposed to her.

She shuddered a sigh as Seteth grabbed her hip with one hand, lining up his cocks with her holes. They were both rather inexperienced with this, Seteth due to a long time since having a partner, Byleth with just having very few partners to speak of at all.

Seteth had been meticulous about preparing her, but she mentally prepared herself for at least a slight sting.

“Okay,” Seteth breathed.

Byleth scrambled at the sheets, moaning as he pushed into her.

The tapered ends made it easier, easing her to widen for his lengths as he pressed into her. He barely got the heads in before pausing.

“So tight,” Seteth hissed.

Byleth moaned incoherently. The stretch was perfect, but not quite enough. His hands had an iron grip on her, keeping her still.

“Why aren’t you moving?” she whined.

“I don’t want to hurt you.”

She bucked back to get a little more of him inside of her.

“I can handle it.”

There was an agonizing moment of stillness. Before she could turn around to quip something, he pulled her back as he pushed forward, seating himself fully inside of her.

“Like this? Can you handle me like this?”

“Fuck,” she gasped in lieu of properly answering.

She was so full and her toes curled at the raw sensation of it. Now, she was really glad Seteth had been so thorough about opening her up. He would have torn her apart otherwise.

Seteth hummed. “Lost for words? I thought you said you can handle it.”

He pulled back and pushed back in, grinding hard against her hips. Byleth glanced over her shoulders to see Seteth staring down at her with undisguised lust. She thought about making a joke about how sinful he looked before he started thrusting into her. Clearly, Seteth took that as the words of permission that they were, also taking the challenge that she seemed to offer on instinct.

She turned back towards the bed and grinded her forehead against the mattress as he fucked her. Already, she barreled towards release as her nerves felt alight from the sensation. He was good to her, always, as an ally in battle, advisor, lover.

She demanded much of him throughout the war and during peacetime, as he demanded of her, even after they had confessed their feelings for each other. Needless to say, it created plenty of tension. This felt like a full release, letting go of the stress and lies that kept them from truly knowing each other.

Seteth gave her no quarter, fucking her with steady, punishing thrusts as she writhed and bucked underneath him.

Byleth reached down where their bodies joined and immediately shivered through her orgasm. Seteth growled as she tightened around him.

“Minx.”

“Only for you, of course,” Byleth gasped.

She felt boneless and limp, but Seteth kept her in place on her knees, keeping her pinned against his body. She probably looked like a fucked-out mess, but that didn’t seem to bother Seteth at all. For someone who was so strait-laced all the time, he really liked to see her disheveled, whether it be from fighting or fucking.

“You take me so well.”

She blushed a little at the compliment, feeling a victory as Seteth's thrusts became faster and lost their rhythm.

“You’re getting close?” she whispered. “You’re gonna come inside of me?”

Seteth growled again as his arms wrapped around her. He braced one arm under her breasts and hauled her up onto her knees, pressing her against his chest.

The change in the angle had her wailing, one hand rubbing over her clit to give her some relief and the other desperately grabbing at Seteth’s arm.

He whispered dark things in her ears, about arcane rituals to increase pleasure and stamina, of ropes and walking on a fine line between torture and pleasure, of filling her up with his come. No mentioning of children just yet, though the implication was definitely there. They hadn’t gotten that far into their relationship and the scars of war were too fresh across Fódlan to think about children and rebuilding that aspect of the continent.

She was fine with practicing.

The hand not keeping her braced against his chest wandered over her body, tweaking her nipples and joining her own hand to play with her clit.

He pounded into her with obscene slapping sounds and mouthed at her throat, sucking bruises over the skin and sending shivers down her body.

“I want to come inside of you.”

“Give it to me,” she gasped.

He grinded his hips hard as if in reprimand.

She wondered if the fact that he had two cocks would double the pleasure he felt. The way he huffed and growled as he fucked her, how his hands dug into her flesh, told her that it was likely the case. All she could do was take it and, goddess help her, she was okay with being used in such a way. She had found her pleasure, even now there were little shocks of pleasure that radiated from her core, not enough to bring her orgasm, but enough to have her toes curling with each thrust.

The room was filled with the obscene sounds of skin on skin and animalistic grunts and whines.

Seteth mouthed at her throat, sloppy and inelegant as he got closer and closer.

“Byleth—fuck—fuck!”

The obscenities by themselves were enough to send a shiver down Byleth’s spine. She sobbed as he pulsed inside of her and his teeth sunk into her shoulder. It felt like an eternity of him rocking against her, making unintelligible sounds. It was as if he wanted to milk every drop inside of her.

Seteth kept her against his chest as they both caught their breath. His seed already dripped down her thighs before he could pull out.

Byleth made a tiny noise as he pulled out of her, feeling suddenly empty. He rested her on the bed and she stared up at him with bleary eyes. She couldn’t help but glance down at his hips. Seteth shifted a little at the attention, but didn’t move to cover himself.

Instead, his focus was on her. He crawled forward on the bed, looking almost predatory.

“You look like something out of a sinner’s novel,” he murmured.

Seteth stroked his fingers over her inner thighs, from her knee down towards her pussy.

“Look at you. You’re dripping with me.”

She blushed. “You _sound_ like someone out of a sinner’s novel,” she replied.

His fingers skimmed between her legs and collected some of the seed dripping out of her. She watched and shivered as he pushed his seed back inside of her. His fingers rubbed against her walls and she shifted as the warmth of arousal sparked anew, despite how many times she had come and how thoroughly he had used her.

Then, there was that immediate twinge of discomfort and she swatted at his hand.

“No more,” she breathed.

Seteth pulled his hand away and instead went for the water and rags they had set aside. He cleaned her thighs and over the space between with soft, soothing motions. He kissed over the bruises he had pressed into her skin, all the while whispering praises about how beautiful she was.

Byleth wasn’t good at praise or aftercare like Seteth was. She managed, when it was her turn to take Seteth apart. She particularly liked how he took care of her, so she wouldn’t mind being in this position more often.

“I can brush your hair too if you’d like.”

Tempting, as she knew that her hair was likely a mess. That was another thing that he was good at.

“A nap, first,” Byleth mumbled.

She reached up and pressed her hand over his chest to feel his beating heart. It still seemed to race under her touch, as if he was still riding the high of their earlier activities.

“Lovely,” she murmured.

Her hand dropped away before she held her arms out in askance. Seteth put away rags before nestling in her arms. His weight should have been uncomfortable, near-crushing, but she found it particularly grounding.

“Was it too much, my dearest?” Seteth asked between her breasts, as if afraid of the answer she would give. “It’s not exactly normal by human standards.”

She laughed, full-bodied, and suddenly she felt lighter than she had ever felt before.

“It was perfect, Seteth.”

**Author's Note:**

> -insert Bad Dragon reference here-  
> Comments and kudos are greatly appreciated! I work in a clinic so days are long and difficult, even more so nowadays.   
> [Here’s my Tumblr! Feel free to follow and drop Setleth drabble/fic requests!](https://tiaraofsapphires.tumblr.com/)  
> [I am also attempting to make my general twitter my writer twitter. Give me a follow there as well!](https://twitter.com/BlooRalts)  
> Cheers!


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